Khashoggi, a prominent critic of Saudi policy, was killed in the country's Istanbul consulate on Oct. 2, after a struggle, by a lethal injection dose and his body was dismembered and taken out of the building, deputy public prosecutor and spokesman Shaalan al-Shaalan told reporters.
He said the Washington Post columnist was murdered after "negotiations" for his return to the kingdom failed and that the person who ordered the killing was the head of the negotiating team that was sent to repatriate Khashoggi.
The whereabouts of Khashoggi's body remain unknown, he said.
Riyadh had offered numerous contradictory explanations for Khashoggi's disappearance before saying he was killed in a rogue operation, in a case that has sparked a global outcry, opened the kingdom to possible sanctions and tarnished the image of Crown Prince Mohammed bin Salman.
Turkish officials have accused Prince Mohammed of ordering the murder while President Erdogan said the killing was ordered at the "highest levels" of the Saudi government. U.S. President Donald Trump has suggested ultimate responsibility lies with the prince as de facto ruler.
"The Public Prosecutor has requested the death penalty for 5 individuals who are charged with ordering and committing the crime and for the appropriate sentences for the other indicted individuals," Shaalan said, without naming the five.
He said 11 out of 21 suspects have been indicted and that their cases will be referred to court, while the investigation with the remaining suspects will continue in order to determine their role in the crime.
A travel ban has been imposed on a top aide to the crown prince, Saud al-Qahtani, while investigations continue over his role, Shaalan said, adding Qahtani had met the team ordered to repatriate Kashoggi ahead of their journey to Istanbul to brief them on the journalist's activities. Qahtani has already been fired from the royal court.
Turkey says it has a recording related to the killing which it has shared with Western allies. President Tayyip Erdogan said the recordings are "appalling" and shocked a Saudi intelligence officer who listened to them, Turkish media reported on Tuesday.